1. Field of the Invention
This invention relates to packaging for film that is manufactured and shipped in roll form. More particularly, the invention relates to a new form of packaging that is designed to offer protection against distortion, abrasion and edge damage for a plurality of rolls per package of synthetic plastic film.
2. Description of the Prior Art
Transparent film made from synthetic plastic is in widespread use for packaging cuts of meat, cheese, and other foodstuffs and materials. Plasticized polyvinyl chloride and polypropylene are synthetic plastic materials often used in making plastic wrapping film.
This kind of film is usually manufactured, sold, and shipped in the form of rolls. To make a film roll, a web of the plastic film, of predetermined width, is wrapped around a rigid tubular core. The core is often made from heavy cardboard or other suitable, inexpensive material. Because the film is easily damaged, and thermoplastic, it requires careful handling during manufacture, careful packaging and handling during shipment, and care during dispensing from the roll and use. Damage may take the form of distortion, abrasion that mars the transparency of the film, or damage to the film edge that might lead to a variety of undesirable consequences. Edge damage to the film in a roll, for example, tends to interfere with the orderly dispensing of the film from the roll. If the edge damage is severe enough, it may even prevent the film from being unwound without damage, thus rendering some part of the roll useless to the user, with resulting waste.
There have been several attempts to ameliorate these problems in recent years. In one approach, triangular corrugated mandrels are inserted through the bores of the cores of several film rolls, to unitize the rolls on each mandrel. The loaded mandrels are then disposed vertically, so that one roll is, in effect, stacked on top of another. Stability is poor with this arrangement, sometimes leading to damage when the instability causes undesired or unanticipated movement of a stack of the rolls.
In a second approach, foamed plastic has been fabricated into rigid foamed trays that are shaped so that a pair of trays can cradle the ends of several film rolls. The end portions of a given film roll are seated in recesses in a pair of such trays, and each set of trays can accommodate the ends of several film rolls, side by side. The trays are stacked one on the other to make an array several trays high. Metal strapping is then used to secure the set of trays together, to unitize as many as a dozen film rolls. In the usual such design, the film rests directly on the trays, but unfortunately, damage and distortion still results.
In still another approach, master cartons using double end caps are used to unitize rolls, but no means are provided for suspension. The roll of film thus rests directly on the side of the carton, with the consequent opportunity for abrasion and other damage.